Search continues for Canadian filmmaker missing after dive in Florida

ISLAMADORA, Fla. – A search continues today for a Canadian filmmaker missing after a dive off the coast of Florida.

The U.S. Coast Guard says Rob Stewart was reported missing around 5:15 p.m. on Tuesday, near Alligator Reef off the coast of the Florida Keys.

Coast Guard senior chief Nyx Cangemi says water and air crews have been searching for Stewart ever since.

He says volunteers have also joined the search, with 20 volunteer boats and 12 aircraft joining official search crews on Wednesday.

But Cangemi says so far, no sign of Stewart has been found.

Stewart's family has said the 37-year-old had returned to the surface with a partner after a deep dive when his boat crew lost sight of him.

Stewart's sister has said her brother's dive partner fell unconscious while getting onto a boat — an incident that caused a commotion during which Stewart disappeared.

His family is concerned he may have lost consciousness as well.

Stewart was in Florida filming a follow up movie to his 2006 documentary "Sharkwater," called "Sharkwater Extinction," his sister said.

Stewart, a Toronto native, is also known for his documentaries that include "Revolution" and his memoir "Save the Humans."

A global wildlife photographer, Stewart has devoted his career to warning the world about threats facing sharks, other ocean life and humanity in general.

"Sharkwater," which debuted at the Toronto International Film Festival, became an international hit and prompted people around the world to lobby their governments for bans on shark finning.